Method and apparatus for manufacturing sewer pipe and similar articles



1931 H; P. WILLIAMS METHOD AND APPARATUS FOR MANUFACTURING SEWER PIPEAND SIMILAR ARTICLES Filed Jan. 27. 1930 Patented 6, i931 UNITED STATESPATENT OFFICE HERMAN P. WILLIAMS, ST. LOUIS, MISSOURI, ASSIGNOB TOLACIEDE-OEBISTY CLAY PRODUCTS OOMPANY, OF ST. LOUIS, MISSOURI, ACORPORATION OF MISSOURI I ME'1 HOD AND APPARATUS FOR MANUFACTURING SEWERPIPE AND SIMILAR ARTICLES Application filed January 27, 1930. Serial No.423,785,

.10 the kind that are produced by compressing mud or tempered clay,andthen forcing saidmaterial through an extruding die. While my inventionis particularly applicable to the manufacture of sewer pipe, in that itovercomes an inherent. objection or defect of conventional methods andapparatus used in the manufacture of sewer pipe, I wish it to beunderstood that my invention is applicable to the manufacture of variousother ceramic articles, as my broad idea consist in Sllb180ting loosematerial that is being converted into a ceramic article, toa-compressing operation,

which is of such a character that during the first portion oftheoperation air which may be effectively expelled from same.

Figure 1 of the drawings is a vertical sectional view of an apparatusembodying my invention for manufacturing sewer pipe and similararticles;

Figure 2 is an enlarged top plan view of the plunger of the claycylinder, taken on the line 22 of Figure 1, looking in the directionindicated by the arrows; and

Figure 3 is a vertical sectional view of said plunger, taken on the line3-3 of Figure 2.

The conventional press or apparatus used inthe manufacture of sewer p1peor similar articles that are produced by forcing highly compressedplastic material through an extruding die, comprises a cylinder, usuallyre- 'ferred to as a clay cylinder, open at one end and provided at itsopposite end with an extruding die, a reciprocating plunger fittingloosely in said cylinder and provided with a flat face adapted to act onloose or unpacked mud or clay in said cylinder and disposed at rightangles to'the side wall of the cylinder, and an actuating mechanism forsaid plunger which usually consists of a steam cylinder be mixed with ortrapped in said material will having a piston of considerably greaterarea than the plunger of the clay cylinder and rigidl connected to saidplunger by a piston ro Loose or unpacked mud or clay that has beentempered, mixed or subjected to such treatment as to make it plastic, isfed by a suitable feeding apparatus into a hopper mounted on theopen'end of the clay cylinder, and the reciprocating movement of theplunger of the clay cylinder causes the material in said cylinder to becompressed, moved longitudinally through the clay cylinder and thenforced through the extruding die at one end of said cylinder. The loosematerial that is delivered to the hopper of the clay cylinder is in theform of lumps or particles of irregular shape and size, and as thepressing face of the plunger is flat or disposed at right angles to theside wall of thecylinder, gobs or slugs of. air are liable to becometrapped in the voids or spaces between the particles of material duringthe first portion of the operation of compressing or compacting theparticles of loose material together, which trapped air subsequentlybecomes compressed to a high degree during the final compressingoperation or during the operation of forcing the compressed materialthroughthe extruding die. These gobs or slugs of highly compressed airremain trapped in the material until the shaped or formed article leavesthe die, whereupon said gobs or slugs expand, and often producedisastrous results to the article being formed. If an article having arelatively thin wall is being produced, there is not sufficient materialaround an air pocket to withstand the internalpressure of the pocketafter the portion of the material containing said pocket has passedthrough the extruding die, and the result is, that said portion will beruptured by the expansion of the air, thus making the article unfit forcommercial use. If the article being produced has a relatively thickwall, there may be suflicient material in the wall to prevent the wallfrom being ruptured by an internal air pocket, but even in thick walledarticles internal air pockets are highly objectionable, as they produceweak spots or spots in which the material is of laminated structure.

In order to overcome or remedy the above mentioned defects or objectionsto the conventional method and apparatus used in the manufacture ofsewer pipe and similar arti-' cles, I propose to subject the loosematerlal ing die. Usually, the loose, tempered material that isintroduced into the clay cylinder will be subjected'to pressure by theaction of a reciprocating plunger provided with a pressing surface ofsuch shape or form that the pressure will be first applied to the centerof the mass of material in the clay cylinder and then appliedprogressivel towards the side wall of said cylinder, there y causin anyair which may be mixed with the material at the center of the mass onwhich pressure is exerted to escape to a polnt of exlt, and

hence, not become trapped in a pocket, andthereafter subjected to adangerous pressure or excessively high pressure as the materialcontinues to move longitudinally through the clay cylinder towards theextruding die. 7

The material travels longitudinally through the clay cylinder and thedensity of said material increases progressively as the mass of materialap roaches the lower end of the clay cylinder. ence, the loose materialthat is introduced into the upper end of the clay cylinder will besupported by or sustained by a mass of highly com ressed or densematerial which forms in e ect an opposing wall for the reciprocatingplunger,

and at each downward stroke of sald plunger the loose material which theplunger engages or acts upon will be subjected to considerable pressurethat is applied to same, first at the center of the mass of loosematerial and thereafter progressively towards the side wall of the claycylinder, as above described. From the foregoing it will be seen thatthe .loose material which is introduced into the clay cylinder is notcompressed by a single stroke of the reciprocating plunger, but that onthe contrary, said material is compressed progressively by successivestrokes of the plunger, and moved progressively through the claycylinder towards the extruding ie of the lower end of said cylinder, therepeated actions of the plunger and the shape of said plunger causingany air which may be mixed with or trapped in the loose materialintroduced into the upper end of the clay cylinder, to be removed beforethe material in the clay cylinder becomes dense or highly compressed. h

'Various means may be employed to attain the hi hly desirable resultabovedescribed, but-I ave found that if the plunger of the clay cylinderis provided with a substan- ,plunger causes lumps or relatively largeparticles of material supported by the compressed mass of material inclay cylinder to e first distributed more or less uniformly throughoutthe circumference ofthe cylinder I and then subjected to a compressingoperation which causes air mixed with said material to be expelled andforced upwardly around the peripheral edge of" the plunger or throughopenings in the plunger, during the'final steps of compressing thematerial to a high degree and forcing it through the extruding die, anyremaining air in the ma terial will be effectively expelled from same.

In the accompanying drawings which illustrate an apparatus constructedin accordance with my invention, A designates a cylinder, which, forconvenience, I have referred to as a clay cylinder, that is arrangedvertically and provided with an open upper end that communicates with ahopper B into which tempered clay or. other suitable loose material isadapted to be fed by a suitable feeding apparatus (not shown). At thelower end of the cylinder A is an extruding die 0 of any suitable typeor kind through which highly compressed. material in the cylinder A isadapted to be forced by pressure exerted on said material by a. plungerD, which is reciprocated longitudinally of the cylinder A b a piston Emounted in a cylinder F that as supply pipes 1 connected to theoppositeends 0 same so as to permit an operatin medium to be admitted to andexhausted rom the cylinder F, the operating piston E being rigidlyconnected with the plunger D by means of a' piston rod 2.

The plunger D, instead of having a flat pressing face disposed at rightangles to the side wall of the cylinder A, has a tapered or inclinedpressing surface whose central portion a; protrudes beyond theperipheral edge 'material that has been introduced into the cylinder Awill be subjected to pressure that is applied to or exerted on saidloose material progresslvely from the longitudinal center of thecylinder towards the side wall of same.

If the loose material in the cylinder A is in the form of lumps orrelatively large par ticles, the downward stroke of the plunger 1)causes the loose material at the upper end of the cylinder A to bearranged more or less uniformly -throughout the circumference of thecylinder, due, of'course, to the fact that zoo the tapered protrudingportion of the pressing surface of the plunger D, upon coming in contactwith the loose material, spreads the same or throws it laterally towardsthe side wall of the cylinder. As the downward movement of the plunger Dcontinues, the center portion of the mass of loose material in thecylinder A will first be subjected to pressure, with the result that anyair which may be in the voids or spaces at the center of the mass willbe displaced or expelled, and" thus forced laterally or radially throughthat portion of the loose material on which pressure has not yet beenexerted by the plunger. In this way each downward stroke of looseplunger D causes the material in the upper been mixed with the loosematerial in the upper end of the cylinder A will have been expelled fromsamev and forced upwardly through the space between the peripheral edgeof the plunger D and the sidewall of the cylinder A. If desired, theplunger D may be provided with relief ports or openings 3 located nearthe peripheral edge of the plunger up through which expelledor'displaced air can flow during the progressive compressing action ofthe plunger D on the material in the cylinder A. Afterthe compressingoperation just described in which any air mixed with the loose materialin the upper portion of the cylinder A is expelled from the material,said substantially air free material travels downwardly through thecylinder towards the die C, and in its downward passage throughthecylinder said mate rial becomes compressed to' ahigh degree, as

is usual in apparatus of this general type.

From the foregoing it will be understood that in my improved method ofmanufacturing ceramic articles, loose tempered clay or the like is fedprogressively or intermittently into the upper end of acylinder, and issubjected to a compressing operation in said cylinder by a reciprocatingplunger whose repeated actions expel air from the loose material that isfed into the upper end of said cylinder, and thereafter compress saidair free material to a high degree and force it through an extruding dieat the lower end of the cylinder.

I claim as new and desire to secure by Letters Patent is:

1. A method of manufacturing sewer pipe and similar articles,characterized b introducing loose material into a cylin er subjectingthe material in the receiving end portion of the cylinder to pressurethat is applied to said material progressively from the center towardsthe side wall of the cylinder, thereby causing air that is'mixed withsaid loose material to be expelled from same, and thereafter compressingsaid material to a high degree and forcing it into a shaping die.

2. A method of manufacturing sewer pipe andsimilar articles,characterized by intermittently introducing loose material into acylinder that contains a mass of compressed or dense material, andcausing the loose material in the receiving end portion of said cylinderto be acted on by a reciprocating member that progressively exertspressure on.

said loose material from the center of the mass towards the side wall ofthe cylinder.

3. A method of manufacturing sewer pipe and similar articles,characterized by introducing loose plastic material into a cylinder ontop of a mass of compressed or dense material in said cylinder, andexerting pressure on the material in the receiving end portion of saidcylinder in such a way as to first distribute said loose materialsubstantially uniformly around the circumference of the cylinder, andthereafter cause said loose material to be compressed progressively fromthe center of the mass towards the side wall of the cylinder, wherebyair that may be mixed with said loose materialwill be expelled fromsame.

4. A method of manufacturing sewer pipe and similar articles,characterized by introducing a loose plastic material into a cylinder ontop of a mass of dense material in said cylinder, and subjecting theloose material in the receiving end portion of said cylinder to theaction of a reciprocating compressing device that progressivelycompresses said loose material and causes air mixed with the portion ofthe material which is first compressed, to be expelled from same andforced towards a point of exit.

5. An apparatus for producing sewer pipe and similar articles,comprising a verticallydisposed cylinder that is adapted to have loosematerial introduced intermittently into the upper end of same onto amass of dense or compressed material in said cylinder, a reciprocatingplunger operating in said cylinder and provided with a pressing surfaceshaped so that the pressure which said plunger exerts on the loosematerial will be applied progressively from the center of the mass ofloose material in the cylinder to- -.which air expelled from said loosematerial can escape from the cylinder, I, 6. An apparatus for producingsewer pipe and similar articles, comprising a verticallydisposedcylinder open at its up er end, an s extruding die at the lower end saidcylinder, a plunger provided with a substantlally cone-shaped pressingsurface, and means for reciprocating said plunger so as towithdraw 6 itfrom the open upper end of the cyl nder,

thus ermitting plastic material to be ntroduced into the cylinder andthereafter introduce said lunger into the cylinder so as to compress thematerial in the upper end of the cylinder and expel air from saidmaterial.

7. An apparatus for producing sewer pipe and similar articles,comprising avertically- I I disposed cylinder open at its upper end, a

- hopper communicating with the upper end go of said cylinder into whichplastic material is adapted to be fed, an extruding die at the lower endof said cylinder, avertically reciprocating plunger arranged to traveldownwardly through said ho per andenter said cylinder, a pressing surace on said plunger having a tapered central protruding portion, andmeans 'for reciprocating said plunger.

8. In the manufacture of ceramic articles, the procedure consisting ofsubjecting a confined mass of loose material to pressure applied in adirection to substantially expel air thatis mixed with or incorporatedin said material, and thereafter subjecting said substantially air freematerial to suficient pressure to convert it into a dense mass v 'thatis substantially free from highly compressed, trapped air.

9. In the manufacture of ceramic articles, the procedure consisting ofsubjecting a mass 40 of loose material to pressure applied in such a weas to substantially expel air that is mixe with or incorporated in saidmaterial, and thereafter converting said substantially air free materialinto a dense body and forcing it into a shaping die.

10. In the manufacture of ceramic articles, the procedure consisting vofsubjecting a confined mass of loose material to pressure exerted on thecentral portion of the mass and thereafter applied progressively towardsthe peripheral portion of the mass for the purpose of expelling air fromsaid material, and thereafter compressing said substantially air .freematerial to a high degree and 5,5 forcing it into a shaping die.

HERMAN P, WILLIAMS.

